Question

How many grams of water are needed to react with 15.0 grams of li2o? given: li2o+h2o→2lioh?

Answer 1

Answer is: 9 grams of water are needed to react.
Chemical reaction: Li₂O + H₂O → 2LiOH.
m(Li₂O) = 15 g.
n(Li₂O) = m(Li₂O) ÷ M(Li₂O).
n(Li₂O) = 15 g ÷ 30 g/mol.
n(Li₂O) = 0,5 mol.
From chemical reaction: n(Li₂O) : n(H₂O) = 1 : 1.
n(H₂O) = 0,5 mol.
m(H₂O) = 0,5 mol · 18 g/mol.
m(H₂O) = 9 g.

Answer 2

Answer:

9.04 g of $H_{2}O$ are needed to react

Explanation:

According to balanced equation, 1 mol of $H_{2}O$ reacts with 1 mol of $Li_{2}O$

Molar mass of $Li_{2}O$ = 29.9 g/mol

Number of moles = (mass)/(molar mass)

So, 15.0 g of $Li_{2}O$ = $\frac{15.0}{29.9}$ moles of $Li_{2}O$

So, moles of $H_{2}O$ are needed to react = $\frac{15.0}{29.9}$ moles

Molar mass of  $H_{2}O$ = 18.02 g/mol

So, mass of $H_{2}O$ are needed to react = $\frac{15.0}{29.9}\times 18.02g=9.04g$